The invention concerns a magnifying glass of the type described in the introductory clause of claim 1. If necessary, in order to be able to use a higher magnification than that provided by the primary lens, the primary lens is provided with an eccentrically positioned secondary lens. This assembly, which consists of a primary and a secondary lens, will be referred to below simply as a lens combination.
In the previously known magnifying glass of this type (Prym company publication entitled xe2x80x9cUniversal-Lupexe2x80x9d [Universal Magnifying Glass]), the lens combination was rigidly connected with the part of the frame that holds it. The frame was secured to the user""s body by means of attachment, which consisted of a hinged bracket mounted on the frame. The bracket fit around the user""s neck. The position of the lens combination relative to the user""s eyes could be varied by a swivel connection between the frame part or by changing the support position of the frame, on the one hand, and of the bracket on the user""s body, on the other hand. Apart from the fact that these position changes of the frame were difficult to make, unfavorable positions of the secondary lens were produced, which could not be satisfactorily corrected by changing the position of the head or of the work.
In a bifocal magnifying glass (DE-AS 14 97 658), it is well known that a segmented magnifying glass part can be mounted on a spherical support lens. This lens is intended as an aid to vision for persons with poor vision, and the magnifying glass part is held in the desired position in front of the eyes. Rotation of this lens combination is neither intended nor permitted.
A bifocal magnifying glass of another type (DE-OS 21 46 043), which is designed to be secured on one eye, uses a stationary, nonrotatable primary lens and a separate secondary lens with a center of gravity arranged eccentrically to the principal axis of the magnifying glass. The secondary lens is held in an inner groove of the mount, independently of the primary lens, and is able to turn by the force of its own weight. Regardless of how the bifocal magnifying glass is placed in front of the eye, the secondary lens rolls in front of the primary lens until its center of gravity assumes the lowest position in the inner groove. Joint rotation of the secondary lens with the primary lens is neither intended nor suitable.
The goal of the invention is to develop an inexpensive, reliable magnifying glass of the type specified in the introductory clause of claim 1, which can be conveniently adjusted to the specific working conditions. In accordance with the invention, this goal is achieved by the measures specified in the characterizing clause of claim 1, which have the following special significance.
Its rotatable mounting in the frame allows the lens combination of the invention to be brought into a rotated position in which the supplementary lens can be brought into the desired specific position relative to the work. If there is a change in the angle of view and/or the position of the work, the changed position of the secondary lens that is now desired can then be readjusted by rotation. Since the adjustment of the magnifying glass can be adapted to the given working conditions by its rotatable mounting in the frame, the position of the frame on its support surface or on the place of support on the user""s body does not need to be changed. Optimum use of the magnifying glass is always possible.